In collaboration with the Tromsø Aquaculture Research Station and UiT – the Arctic University of Norway, the Norwegian Institute of Food, Fisheries and Aquaculture Research (Nofima) has established brand new facilities with recirculating aquaculture systems (RAS) in order to provide more relevant research for the RAS industry, particularly in the area of disease studies.
Infection models are important tools in fish health research, and must resemble real conditions in aquaculture operations as much as possible. Currently, RAS facilities dominate salmon production, and infection models must be reassessed and adapted to RAS.
Recently, the first infection trials were carried out in the new facility by Nofima. The conclusion after the first experiments is that the infection models worked very well and that the RAS trials can be carried out in less time compared to trials conducted in flow-through systems.
Nofima said disinfection strategies have played a key role in the trials that have taken place so far.
"In the RAS trials, we have simulated, among other things, how pathogenic bacteria get into the RAS facilities," said Carlo C. Lazado, senior scientist at Nofima. "This allows us to study how disease develops in the fish, while at the same time we can investigate how and where the pathogens establish themselves and spread throughout the system."
In previous reports, Nofima has pointed out that many RAS facilities in Norway and North America have disinfection protocols, but it is uncertain how effective these protocols are if pathogens such as viruses and bacteria enter the system.
"Several trials conducted in the new RAS facility will provide us with knowledge about critical areas in the system where the pathogens potentially thrive," said Lazado. "This knowledge will be crucial for us in developing risk assessment protocols in RAS, but even more importantly, in developing disinfection protocols that are effective following a disease outbreak."
Nofima said the RAS facility in Tromsø is the first of its kind where it has been reported that this type of controlled bacterial infection trial on salmon has been carried out.
"When we recently conducted a trial with the pathogen Yersinia ruckeri, we saw that disease developed faster than in flow-through systems, said Lill-Heidi Johansen, fish health scientist at Nofima. "The fish were also susceptible to experimental infection at a different stage in the production cycle compared to what we have observed before. This provides more flexibility in infection trials. In addition, we will test virus infection in the system to see if the same tendencies are observed."